Surface treatment of glass and apparatus therefor



Nov. 21, 1967 CHAUMQNT 3,353,304

' SURFACE TREATMENT OF GLASS AND APPARATUS THEREFOR Filed June 11, 19652 Sheets-Shet 1 HEN/e/ JUL 5 O/AI/Mm/T 32 @MMW Nov. 21, 1967 H- J.CHAUMONT SURFACE TREATMENT OF GLASS AND APPARATUS THEREFOR Filed June11, 1965 '2 Sheets-Sheet 2 United States Patent Office 3,353,304Patented Nov. 21, 11967 13 Claims. (cl. 51-119 The present inventionrelates to the grinding and polishing of sheet glass by means of padswhich are positively moved relatively to the sheet while in contacttherewith. More particularly the invention relates to the situationwherein the grinding or polishing is effected by pads which move in apredetermined orbital or like path while the sheet of glass moveshorizontally in the direction of its length between them.

It is a purpose of the invention to provide a device of the characteraforesaid, wherein the movement of each surfacing pad is effected by twoseparate parts or cranks moved in synchronism with identical movementsor rotations.

Another object is to provide an apparatus wherein the pad is connectedwith two power-driven blocks through a linking structure which providesa limited freedom of expansion or contraction between said blocks.

Another object is to provide an apparatus wherein the pad is connectedwith its power-driven operating means, through an articulated system orlinks which, while effecting positive movement of the pad directly inaccordance with the corresponding movement of the powerdriven cranks, atthe same time permits free movement of the pad toward and from the work,in a direction normal to the surface of the sheet so that force appliedto the pad in the aforesaid direction is directly and fully applied tothe work, resulting in uniform pressure of the pad upon the surface ofthe sheet.

A further object in accordance with that of the preceding paragraph, isthe provision of an apparatus wherein the pad is free to move normal tothe surface of the sheet so that it remains in full surface contacttherewith and engages the sheet with even and uniform pressure until theapplied forces are manually or automatically changed.

Another object is to provide an apparatus as aforesaid which assures theprecise and accurate execution of the orbital or other desired motion ofthe grinding or polishing pad at all times, under all conditions of use,and irrespective of the particular value of the pressure of the pad uponthe sheet, while allowing free manual of surfacing machines and whichaccurately transmits and reproduces the motion of its power-drivenmechanism to the surfacing plate or frame and the pad carried v thereby.

The foregoing and other objects and advantages are attained by a systemof three links and two cranks or other mechanical means for initiatingthe desired orbital movement. The first or central of the three links ispivoted on a first axis to the polishing pad plate or frame. The secondlink is articulated at one end to a corresponding end of the first linkand at its other end to one of the cranks, while the third link isarticulated at one end to the other end of the first link and at itsother end to the other crank. Other links are used to effect directconnection between the cranks and pad frame to assure that the padaccurately and positively reproduces the orbital or translatorymovements of the driving means. The resulting structure is indeformablein a plane parallel with the surface of the sheet, but readily permitsor adapts itself automatically to movements normal to said plane.

The structure will further permit and adapt itself to accidental limitedvariations of the distance between the two power-driven means, such aswould occur because of heat-expansion of the supporting frame or of aslight variation in the synchronism of these means.

Furthermore, because of the novel construction, the two cranks or otherpower-driven moving means impart equal forces to the linkage, so thatthere is no resultant force which might otherwise tend to distort ordeform the same. Nor is there any resultant force developed by thelinkage normal to the plane of the sheet. As a result, the operation issmooth, even and uniform. Pressure is uniform over the area of the padand can be accurately gaged to assure a superior and accurately finishedsurface on both faces of the sheet.

The invention will be readily understood from a study of the followingdetailed description, in connection with the accompanying drawing.

In the drawing:

FIGURE 1 is a perspective view showing one embodiment of the invention;

FIGURE 2 is a side elevation showing a construction in which the pad isarranged for surfacing the lower surface of the sheet of glass, anddepicting the three interpivoted links forming an important feature ofthe invention;

FIGURE 3 is a cross section in a plane identified by line ?i3, FIGURE 2,looking in the direction of the arrows;

and

FIGURE 4 is a plan view of the apparatus of FIG- URES 2 and 3, as seenfrom above.

Referring more particularly to FIGURE 1, 1 and 2 represent first andsecond driving elements shown in the form of rectangular or squarethrust blocks each driven by a respective one of a pair ofvertically-disposed crankshafts 1a and 2a. The crank of shaft 1a isjournaled t0 element 1 by an antifriction bearing 1b. A correspondingbearing 2b connects the crank of shaft 2a to and centrally of element orblock 2. The cranks have equal throws and the shafts are so arranged,interconnected and driven, that their crank radii are at all timesparallel. Any suitable means such as gears, chain and sprockets, shaftsand bevel gearing, etc, may be provided to interconnect the two shaftsfor synchronous rotation in the same direction.

At 10 there is identified a rectangular plate, beam or frame, to theunder side of which, in a known way, a polishing pad 17, FIGURES -2 and3, may be attached.

A U-shaped bracket 9 has its central or bight portion secured at 10acentrally to the face of frame 10 opposite to that to which the pad isattached. A first link 5 has aligned trunnions 5a extending from itscentral portion. These trunnions are pivoted at 8' in the ends of theupstanding arms of bracket 9 so that the link is pivotable about an axisparallel with frame 10 and, when the device is operating, parallel withthe surface of the sheet of glass being worked..A second link 3 has oneend pivotally connected to element 2 at 6, and its other end pivoted tothe adjacent end of link 5 at 3a. A third link 4 has one ribbed forgreater rigidity. Links 3 and 4 are formed with forked ends. Referringto link 3, one forked end thereof embraces the contiguous end of link 5and a pivot pin not shown, passes through aligned holes in the twolinks. Likewise the other forked end of link 3 embraces a pierced lug 6aintegrally attached to one side edge of element 2, and a second pivotpin passes through aligned holes in the lug and link.

Link 4 is essentially like link 3 in shape, size and effective length.Its pivotal connection with link may be a duplicate of thatinterconnecting links 3 and 5. However, element 1 has a lug 1cupstanding from its top surface as viewed upon FIGURE 1, and adjacentand parallel with one side edge thereof. This lug is pierced and a pivotpin passes through and is secured in the aligned holes of the lug andforced end of the link. The construction and arrangement are such thatplates or elements 1 and 2 are normally coplanar despite a smallangularity of link 5 with respect to the plane of frame 10. Thus links 3and 4 While normally essentially parallel with the plane of frame '10are at slightly different elevations thereabove.

The linkage thus described resists twisting of frame about a normallyvertical axis, with respect to elements 1 and 2, as well as about ahorizontal axis parallel with the longitudinal axis of the frame, butpermits limited vertical displacements between the frame and elementswithout, however, varying the relation between the effective lengths ofthe links, that is, their lengths projected upon the plane of frame 10or, in operation, upon the plane of the sheet of glass being surfaced.

In order to transmit to the frame and its pad, component movements ofblocks -1 and 2 in the direction parallel with the plane of the frame,and transversely of its longitudinal axis, additional linkageconnections are provided. Referring first to block 1, a notch 1d thereinreceives one end of a link 11 with a pivotal connection between themabout an axis parallel with the longitudinal axis of the frame. AU-shaped bracket has its central bight portion rigidly attached at A tothe upper surface of frame 10 adjacent one side edge thereof. The

upper ends of the arms of thisbracket are pivotally connected at "13 tothe other end of link 11. A similar link 12 connects element 2 to frame10; and since the connection is-a duplicate of the one just described,itwill be sufficient to identify bracket 16 secured at B to frame 10,line 12 pivoted at one end at 14 between the distal ends of the arms ofbracket 16, and at its other end within notch of thrust block or element2. It will be noted that the axial width of links 11 and 12 in andbetween the arms of brackets 15 and 16, respectively, is a little lessthan the separation between the arms. Thus each link has a limitedamount of axial movement or play between the arms of its bracket'topermit expansion due to heat and undue friction otherwise caused by suchexpansion.

FIGURES 2, 3 and 4 schematically illustrate the general arrangement ofparts when the apparatus is disposed to Work upon the lower surface ofthe sheet of glass. In

thesefigures the thrust blocks '1 and 2, links 3, 4, 5, 11 and '12, andbrackets 9, 15 and 16 are related as previously described in connectionwith FIGURE 1. In FIGURE 2, bracket 15 and link '11 have been omitted toavoid obscuration of one of the thrust rods to be described.

In FIGURES ,2'and 3, 23 identifies generally a'base or frame of themachine and havingspaced vertically-disposed aperturesor guides 24 and25 in which are mounted casings 26 and 27, respectively. These casingsmay be hollow and contain the mechanism indicated at 1a and 2a,

respectively, FIGURE 1, to protect the same against damage from grindingcompound, moisture, dust and dirt. The upper surfaces of these casingsare fiat and coplanar, and each supports its block 1 and 2 for slidingon its surface'by and in response to rotation of shafts 1a and 2a. It iscontemplated that antifriction thrust bearings of known constructionwill be provided between the upper surface of each casing and its thrustblock 1 or 2, as the case may be.

In the construction being described, means are provided to mechanicallyvary the elevation of pad frame 10 with respect to blocks 1 and'2. Thus,block 1 has a pair of transversely spaced lugs fixed to its upper face,

as the parts are viewed upon FIGURES 2 and 3, and forked to pivotallyreceive between them the respective ends of threaded rods 21 and 30.Similarly, frame 10 has a pair of forked lugs 31, 32 fixed to its lowersurface and forked to pivotally receive the ends of threaded rods 20 and33. All axes of pivotal connection, as between 21 and 28 for example,are normal to the plane of FIGURE 3. A turnbuckle 22 interconnects rods20 and 21 so that, in the usual way, turning thereof in one direction orthe other correspondingly varies the spacing of the frame with respectto the blocks. Likewise, rods 30 and 33 are connected by turnbuckle 34which may be actuated to similarly increase or decrease the separationof these rods. In this way the elevation of the continguous end of frame10 above block 1 may be varied.

A similar pair of rods and turnbuckles adjustably connect block 2 andthe other end of frame 10. Since these are duplicates of those describedin the preceding para graph, it is suflicient, referring to FIGURES 2and 4, to identify one turnbuckle 19, rods 35 and 36 connected thereby,and forked lugs 37 and 38 fixed, respectively to block 2 and frame 10.

Thus, by equal rotations of all four turnbuckles a precise and fineadjustment may be effected, of the elevation of frame 10 with respect toblocks 1 and 2. It is contemplated that in addition to or insubstitution for the aforesaid turnbuckle adjustment feature, casings 26and 27 may be made vertically adjustable each in its aperture '24, 25,with respect to frame 23. Such adjustment may be made by mechanically,pneumatically or hydraulically operated means, not shown. The adjustmentthus provided for is within small limits and is compensated by a slightpivoting of links 3, 4, 5, 1-1 and '12 and which in no way affects theaccuracy of operation of the invention. Referring to the componentmotion of the assembly in the direction parallel with the longitudinalaxis of frame 10, it is noted that the forces applied by shafts 1a and2a necessary to produce this motion, are applied equally to link 5 bylinks 3 and 4, so that there is no tendency of this link to pivot inresponse to such forces. Thus, considering FIGURE 2, motion of link 4 tothe right by force applied through block 1, tends to pivot link 5clockwise, while motion of link 3 in the same direction as the result offorce applied by block 2 tends to pivot link 5 counterclockwise. The twotorques thus exerted upon link 5 annul one another and have no tendencyto pivot it about axis 8. Changes in spacing between the blocks, on theone hand, and frame or plate 10 on the other, are automaticallycompensated by a slight relative pivoting between links 3, 4 and 5without, however, any change in the orbital or other motion applied 'tothe frame by shafts 1a and 2a.

If the distance between blocks 1 and 2 is accidentally modified, links3, 4 and 5 will pivot slightly and automatically'adjust themselves tothe new distance separating blocks 1 and 2.

The operation will be clear from the foregoing description and isbriefly rsumd. The sheet of glass on a conveyor notshown and movingcontinuously in the direction of its length is supported at a locationin its travel, by one ormore of the frames 10 as depicted upon FIGURE 2,each equipped withapad 17 and continuously supplied by known means, withgrinding or polishing compound. Likewise a second one or plurality ofdevices as in FIG- URE 1 'will be in contact with and operating upon theupper face of the sheet at the aforesaid location. The arrangement issuch that the entire .area of the sheet Of glass on both faces thereofis worked upon 'by the pads. In the case of the pad contacting the upperface of the sheet, the weight of the frame may be assisted byhydraullically or pneumatically-operated means to exert a controlleddownward thrust upon the frame in a manner similar to that applied bythe turnbuckles of FIGURES 2, 3 and 4.

In a manner clear from inspection ofthe drawing and from the previousdescription, the component of motion of blocks 1 and 2 in the directionparallel to the longitudinal axis of frame is transmitted thereto bylinks 3, 4 and 5, through bracket 9. Similarly the component of motionparallel to the frame and normal to the longitudinal axis thereof, istransmitted by links 11 and 12 through brackets 15 and 16, respectively.At the same time, necessary adjustments of the upper and lower framesrelatively to the sheet are'manually or automatically effected withoutappreciable change in the motion of the frames. Such adjustments arefrom time to time made necessary by reduction in thickness of the sheetby removal of detritus, wear of the pads, variations in thickness ofglass being processed, and other factors.

In the case of the lower frame whose pad is working upon the lower faceof the sheet, adjustments are readily effected by turning ofturn-buckles 22, 34, etc., or by varying the hydraulic force urgingcasings 26, 27 upwardly, where such force-applying means are provided.In the case of the upper frame the weight of the frame, augmented byhydraulic or pneumatic force-applying means interposed between blocks 1and 2 and the frame, provide automatically for full-area contact at alltimes between the pad and the sheet, and enable the pressure to bemaintained at a constant value which may be increased or decreased asrequired by the particular operation being carried out, e.g., grindingor polishing, the compound used, type of glass, speed of movement of thesheet and numerous other considerations.

I have thus provided a device which fulfills all of the objects stated.Due to the uniformity of pressure of the pads upon the glass, and theprecise control and automatic compensation afforded by the invention,rapid polishing and grinding operations are carried out with a resultingsuperior product having a perfection of smoothness and polish notpreviously attainable.

Since many alterations, modifications, substitutions of equivalents andchanges in shape, size and form will readily occur to those skilled inthe art, after a study of the foregoing description, the disclosureshould be taken in an illustrative rather than a limiting sense. Allmodifications within the scope of the subjoined claims are reserved.

Having now fully disclosed the invention what I claim and desire tosecure by Letters Patent is:

1. In an apparatus for surfacing sheet glass, a plate having a planarsurface to which a pad may be attached for frictional contact with thesheet glass, a pair of thrust blocks, means operable to move said blocksin unison in a predetermined path having mutually-normal componentsparallel to said surface, first link means between said blocks and plateto transmit one of said components of motion to said plate, and secondlink means between said blocks and plate to transmit the other saidcomponent of motion to said plate.

2. A grinding and polishing apparatus for sheet glass, comprising, aplate having a planar surface to which a pad may be secured, and havingmutually normal first and second axes in said surface, a pair of thrustblocks mounted in spaced relation along said first axis, a first linkmounted on said plate for pivoting about an axis parallel with saidsecond axis, second and third links each connected at one end to arespective one of said blocks and at its other end to a respective endof said first link, and power driven means engaging said blocks andoperable to move the same and said plate in a predetermined path.

3. The apparatus of claim 2, said last-named means comprising a pair ofparallel spaced shafts each having a crank at its end journaled to arespective one of said blocks.

4. An apparatus for surfacing a sheet of glass moving in the directionof its length, comprising, plate means having a planar surface overwhich a surfacing pad may be secured, first and second thrust blocksspaced along a first axis in said surface, a first link pivoted betweenits ends to said plate means, second and third links each pivoted at oneend to a respective one of said blocks and at its other end to arespective end of said first link, all pivot axes of said first, secondand third links being parallel with said surface and normal to saidfirst axis, fourth and fifth links each pivoted at one end to arespective one of said blocks and at its other end to said plate means,the pivot axes of said fourth and fifth links being parallel to saidfirst axis, and power-driven means connected with said blocks to movethe same equally and in synchronism in a plane parallel with saidsurface.

5. The apparatu of claim 4, said second, third, fourth and fifth linksbeing substantially parallel with said surface.

6. The apparatus of claim 4, said power-driven means comprising firstand second shafts each mounted with its axis of rotation normal to saidsurface, each said shaft having a crank on its end journaled in arespective one of said thrust blocks, said shafts being rotated insynchronism with their crank radii parallel.

7. Apparatus for surfacing sheet glass comprising, a frame having aplanar surface to which a surfacing pad may be attached, first andsecond spaced thrust blocks, a first link, means pivoting said linkbetween its ends to said frame, second and third links each having oneend pivotally connected with a respective one of said blocks and itsother end pivotally connected with a respective end of said first link,all pivot axes of said first, second and third links being parallel andparallel with said surface, fourth and fifth links each pivoted at oneend to a respective one of said blocks and at its other end to saidframe, the pivot axes of said fourth and fifth links being parallel withsaid surface and normal to the pivot axes of said first, second andthird links, and thrust means between said frame and blocks and operableto vary the spacing therebetween.

8. The apparatus of claim 7, said last-named means comprising a firstplurality of rods of adjustable length each pivoted at one end to saidfirst block and at its other end to said frame, and a second pluralityof rods of adjustable length each pivoted at one end to said frame andat its other end to said second block, the pivot axes of all said rodsbeing parallel with the pivot axes of said fourth and fifth links.

9. The apparatus of claim 7, a base, and means carried by said base andsupporting said blocks for translational adjustment in the directionnormal to said planar surface.

10. An apparatus for surfacing sheet glass, comprising, a plate having aplanar surface to and over which a surfacing pad may be secured, first,second and third bracket means rigid with said plate, first and secondthrust blocks spaced in a first direction parallel with said surface, afirst link pivoted between its ends in said first bracket means, secondand third links each pivoted at one end to a respective one of saidblocks and at its other end to a respective end of said first link,fourth and fifth links each pivoted at one end in a respective one ofsaid second and third bracket means, and at its other end to arespective one of said blocks, said first link being inclined to saidsurface, said second, third, fourth and fifth links being essentiallyparallel with said surface, the pivot axes of said first, second andthird links being parallel and normal to the parallel pivot axes of saidfourth and fifth links, all said pivot axes being parallel with saidsurface, spaced parallel vertically disposed first and secondcrankshafts having equal crank radii, and means journaling the crank ofeach said shaft in a respective one of said blocks.

11. The apparatus of claim 10, and thrust rod means connected betweeneach said block and said plate and operable to vary the separationtherebetween.

12. A grinding and polishing apparatus for sheet glass comprising:

a plate having a planar surface to which a pad may be secured,

a pair of power-driven blocks operable in unison to move said plate in apredetermined path having mutually normal components parallel to saidsurface,

first link means between both said blocks and said plate to transmit oneof said components of motion from said blocks to said plate andproviding limited freedom of expansion between said blocks,

and second link means between each of said blocks and said plate, totransmit to said plate the other of said component of motion.

13. The apparatus of claim 12 and thrust means interposed between saidblocks and said plate to urge said plate in contact with the surface ofthe sheet of glass.

References Cited UNITED STATES PATENTS 10 ROBERT C. RIORDON, PrimaryExaminer.

A. MATHEWS, Assistant Examiner.

1. IN AN APPARATUS FOR SURFACING SHEET GLASS, A PLATE HAVING A PLANARSURFACE TO WHICH A PAD MAY BE ATTACHED FOR FRICTIONAL CONTACT WITH THESHEET GLASS, A PAIR OF THRUST BLOCKS, MEANS OPERABLE TO MOVE SAID BLOCKSIN UNISON IN A PREDETERMINE PATH HAVING MUTUALLY-NORMAL COMPONENTSPARALLEL TO SAID SURFACE, FIRST LINK MEANS BETWEEN SAID BLOCKS AND PLATETO TRANSMIT ONE OF SAID COMPONENTS OF MOTION TO SAID PLATE, AND SECONDLINK MEANS BETWEEN SAID BLOCKS AND PLATE TO TRANSMIT THE OTHER SAIDCOMPONENT OF MOTION TO SAID PLATE.